Theoretical growth of framboidal and sunflower pyrite using the R-package frambgrowth

Merinero, Raúl; Cárdenes, V.

doi:10.1007/s00710-017-0535-x

Cited by 3 publications

(5 citation statements)

References 24 publications

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“…F Py is formed at a high saturation of iron monosulfide, exhibiting semispherical and spherical shapes within the host rock and OM (Figures b and ). By transforming into a core–shell structure Py , E Py and F Py can develop into S Py (Figure a–c). , Figure a shows single crystals of (Fe(II)) polysulfide (E Py ) under normal saturation, while Figure b shows a single crystal of (Fe(II)) polysulfide (F Py ) under rapid nucleation of supersaturated iron monosulfide. , Both E Py and F Py crystals can coexist (Figure ).…”

Section: Resultsmentioning

confidence: 99%

“…By transforming into a core−shell structure Py, EPy and FPy can develop into SPy (Figure 4a−c). 39,40 Figure 2a shows single crystals of (Fe(II)) polysulfide (EPy) under normal saturation, while Figure 2b shows a single crystal of (Fe(II)) polysulfide (FPy) under rapid nucleation 7 of supersaturated iron monosulfide. 41,42 Both EPy and FPy crystals can coexist (Figure 3).…”

Section: Pyrite Varieties Discovered In the Samplesmentioning

confidence: 99%

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Pyrite Dissolution in the Cretaceous Yogou Formation of the Niger (Chad) Basin: Implications for Basin Evolution under a Rift Tectonic Setting

et al. 2022

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This is the first study of pyrite minerals in the entire West and Central African Rift System (WCARS). Several polished organic-rich core samples from the Cretaceous Yogou Formation of the Niger (Chad) Basin located in the WCARS were investigated for their pyrite content using FE-SEM and SEM-EDS imaging techniques. An attempt was made to classify the types and provenance of the pyrites and to highlight the control of rift fractures on the oxidation and dissolution of pyrites in the region. Three major types of pyrites are present in the studied formation, including euhedral pyrite (EPy) crystals, pyrite framboids (FPy), and sunflower pyrites (SPy). A statistical analysis of 307 FPy shows that the framboids are diagenetically formed with an average diameter of 6.61 μm. SPy is present in a relatively low amount compared to framboids. The pyrites underwent a variety of diagenetic modifications, from mechanical compaction to oxidation, dissolution, and recrystallization. Unoxidized pyrites primarily contain Fe, S, and C, but oxidized pyrites also contain O, Al, and Si. There is a strong correlation between the fractures and the spatial distribution of the physicochemical alteration of the pyrite in the study. Dissolution in relatively deep-buried samples occurs mainly along fracture planes. The fractures provide a pathway for oxidants and other metal elements to reach the pyrites. The pattern of pyrite dissolution reflects the timing of fracture formation and fracture activities as a purveyor or drainage for fluids in the organic-rich samples investigated. The pyrites are associated intimately with organic matter (OM); thus, the relationship between the fracture and the pyrites’ transformation is significant in the assessment of organic matter preservation at deep-burial depth.

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Section: Resultsmentioning

confidence: 99%

Section: Pyrite Varieties Discovered In the Samplesmentioning

confidence: 99%

Pyrite Dissolution in the Cretaceous Yogou Formation of the Niger (Chad) Basin: Implications for Basin Evolution under a Rift Tectonic Setting

et al. 2022

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“…3d; cf. Merinero et al 2009Merinero et al , 2017Merinero and Cárdenes 2018). The diameter of this rare variety of framboids varies from 6 μm to 20 μm.…”

Section: Morphology and Size Distribution Of Pyrite Framboidsmentioning

confidence: 99%

“…Cross plot between mean diameter and standard deviation of pyrite framboids. Oxic-anoxic field boundaries are adapted on the basis of published data (cf Wilkin et al 1996;Bond and Wignall 2010;Merinero and Cárdenes 2018)…”

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confidence: 99%

Ooidal ironstones in the Meso-Cenozoic sequences in western Siberia: assessment of formation processes and relationship with regional and global earth processes

Rudmin

Banerjee

Abdullayev³

et al. 2020

J. Palaeogeogr.

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This study investigates the process of formation of ooidal ironstones in the Upper Cretaceous-Paleogene succession in western Siberia. The formation of such carbonate-based ironstones is a continuing problem in sedimentary geology, and in this study, we use a variety of data and proxies assembled from core samples to develop a model to explain how the ooidal ironstones formed. Research on pyrite framboids and geochemical redox proxies reveals three intervals of oceanic hypoxia during the deposition of marine ooidal ironstones in the Late Cretaceous to the Early Paleogene Bakchar ironstone deposit in western Siberia; the absence of pyrite indicates oxic conditions for the remaining sequence. While goethite formed in oxic depositional condition, chamosite, pyrite and siderite represented hypoxic seawater. Euhedral pyrite crystals form through a series of transition originating from massive aggregate followed by normal and polygonal framboid. Sediments associated with goethite-chamosite ironstones, encompassing hypoxic intervals exhibit positive cerium, negative europium, and negative yttrium anomalies. Mercury anomalies, associated with the initial stages of hypoxia, correlate with global volcanic events. Redox sensitive proxies and ore mineral assemblages of deposits reflect hydrothermal activation. Rifting and global volcanism possibly induced hydrothermal convection in the sedimentary cover of western Siberia, and released iron-rich fluid and methane in coastal and shallow marine environments. This investigation, therefore, reveals a potential geological connection between Large Igneous Provinces (LIPs), marine hypoxia, rifting and the formation of ooidal ironstones in ancient West Siberian Sea.

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“…In the years since, other authors have continued working with populations of framboidal pyrite [1][2][3][4][5][6][7] applied to the determination of paleo-conditions. Of the diverse Minerals 2020, 10, 459 2 of 9 factors controlling framboid growth and morphology, the most important are reactant concentration, temperature and time [1][2][3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

A Morphological and Size-Based Study of the Changes of Iron Sulfides in the Caples and Torlesse Terranes (Otago Schist, New Zealand) during Prograde Metamorphic Evolution

et al. 2020

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It is widely accepted that metamorphism induces a remobilization of iron sulfides, sweeping away original ones while creating new ones. This paper analyzes size distributions of iron sulfides in several samples from the Caples and Torlesse terranes from the Otago Schist (New Zealand) using high-resolution X-ray computed tomography, which allows all iron sulfides larger than the resolution at which X-ray scans were performed to be characterized. Framboids and clusters of framboids are common in unmetamorphosed samples, but disappear in greenschist/amphibolite facies samples, where iron sulfides have anhedral habits. By contrast, the size and standard deviation of the new iron sulfides both remain within the same range. The results illuminate the evolution of iron sulfides throughout metamorphism, proposing boundaries for the metamorphic processes based on the shape of these iron sulfides.

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Theoretical growth of framboidal and sunflower pyrite using the R-package frambgrowth

Cited by 3 publications

References 24 publications

Pyrite Dissolution in the Cretaceous Yogou Formation of the Niger (Chad) Basin: Implications for Basin Evolution under a Rift Tectonic Setting

Pyrite Dissolution in the Cretaceous Yogou Formation of the Niger (Chad) Basin: Implications for Basin Evolution under a Rift Tectonic Setting

Ooidal ironstones in the Meso-Cenozoic sequences in western Siberia: assessment of formation processes and relationship with regional and global earth processes

A Morphological and Size-Based Study of the Changes of Iron Sulfides in the Caples and Torlesse Terranes (Otago Schist, New Zealand) during Prograde Metamorphic Evolution

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